CAB to CPIO Converter

CAB (Cabinet) is a compressed archive format developed by Microsoft) for efficient software distribution and Windows component packaging. Introduced around 1996, CAB files serve as the container format for Windows Installer packages (.msi), Windows system updates, driver distributions, and ActiveX component downloads. The format supports three compression algorithms — MSZIP (Microsoft's Deflate implementation), Quantum (statistical compression), and LZX (an LZ77 variant with Huffman coding optimized for executable files) — with LZX typically delivering the highest ratios. CAB archives organize files into folders (compression units) where files within the same folder are compressed as a continuous stream for improved ratios, and archives can span multiple volumes for distribution on size-limited media. One advantage is deep Windows ecosystem integration — CAB files are handled natively by Windows without third-party software, used in everything from OS installation media to driver packages and system updates. The LZX compression algorithm provides another strength, achieving particularly strong compression on compiled code and PE executables, which is ideal for the format's primary role in software distribution. Microsoft's makecab tool ships with every Windows installation, and CAB extraction is built into Windows Explorer. The format continues to serve as infrastructure for Windows deployment and update mechanisms across enterprise and consumer environments.